While not necessarily confined thereto, the present invention has immediate application to a household electric meter. While some electric meters are located external to the house, as in newer construction, nevertheless the large majority of existing meters are located in the basement of the house. This requires an employee of the utility company to enter the house to read the meter on a regular basis. Even if the home owner should elect to report the meter readings directly, an audit must be conducted occasionally. Because of the existing crime wave and the fear thereof, particularly burglaries, home owners are reluctant to provide a meter reader with a duplicate key, and sometimes are reluctant to allow the meter reader to enter the home while a member of the family is present. Moreover, from the meter reader's standpoint, the job has become increasingly hazardous because of fierce watch dogs, as well as various burglar protection equipment, and the possibility that the home owner may mistakenly perceive the meter reader to be an intruder.
In an attempt to alleviate these problems, others in the art have provided a remote register on the outside of the building to provide readings identical to the readings on the electric service meter within the building. However, none of these attempted solutions are entirely satisfactory and to date have not been commercially implemented on a widespread basis.
More specifically, one device currently available on the market uses a gear drive and a cooperating cam mechanism with mechanical "Form C" contacts as a generator to electrically drive a readable remote register. However, this mechanism adds friction to the meter-driving motor, which introduces potential errors in the reading. Besides, the mechanical "Form C" contacts are subject to problems caused by dirt and corrosion encountered in damp environments; and as a result, this solution is generally undesirable.
Another commercial device for providing a remote meter reading uses a friction-type of wheel monitor having sliding mechanical contacts. While reducing friction to some extent, nevertheless, this device is subject to the same environmental problems and thus is also generally undesirable.
In the overall art of remote metering systems or telemetering systems, examples of the use of mechanical or electromechanical sensing devices are shown in U.S. Pat. Nos. 1,804,576; 2,286,180; and 3,153,780. While perhaps adequate for certain stated purposes, these prior art patents are also unsatisfactory for the intended purposes of the present invention.
Still another attempted commercial solution uses an infra-red photo-optic coupler as a generator for driving suitable recording equipment. While this technique provides frictionless wheel sensing, nevertheless, it is affected by high ambient light near saturation of the sensing cell and thus is restricted to a low ambient light operation. As a result, it is unsatisfactory where basement lights are turned on and off, or where rays of sunlight may enter through a basement window and impinge upon the coupler. In addition, no means is provided to accommodate free play or so called "backlash" of the wheel.
In the overall art of telemetering systems, examples of the use of photoelectric or photosensitive pick-up or sensing devices are shown in U.S. Pat. Nos. 1,750,242; 3,943,498; and 4,281,325. Again, these devices are vulnerable to relatively high light intensity and thus are unsatisfactory for the intended purposes of the present invention.
The commercial prior art has also resorted to the use of a permanent magnet carried by a rotating shaft and cooperating with a magnetic reed switch or a Hall-effect device. However, this attempted solution exhibits poor resolution of the wheel position, especially in the limited space found within a standard household electric meter. Examples of the use of magnetic reed switches for remote telemetering systems are shown in U.S. Pat. Nos. 3,852,726 and 4,296,411. However, these patents are unsatisfactory for the intended purposes of the present invention.
Further, in U.S. Pat. No. 4,237,517, an apparatus is disclosed for monitoring the motion of a shaft used in a conveyorized apparatus. An insulated disc, driven by the shaft, carries a plurality of conductors which pass, sequentially, adjacent to an inductor energized by an oscillator circuit. The presence of the conductive material modulates the amplitude of the oscillations in the circuit. This sensing means produces a series of respective pulses, which cooperate with an electronic control circuit (including a ramp generator means) for monitoring the rate of shaft rotation. This '517 patent is intended for a different application and again, is unsuitable for the purposes intended herein.
Further, in the overall prior art of which I am aware, U.S. Pat. No. 4,001,815 discloses a rotary electromagnet indicator in which a cup-shaped rotor substantially encloses a stator having five salient poles provided with respective windings. The rotor has a hub rotatably mounted on a stub shaft mounted on a printed circuit board. The annular rim of the rotor carries a 0-9 digital sequence. A flat permanent magnet is carried by the rotor hub and has truncated salient magnetic poles formed along a diametral axis. Each of the poles has an angular width which is greater than the equiangular spacing of the stator pole faces by an amount no greater than the angular width thereof. The stator windings can be selectively energized to align a selected pole face of the p.m. rotor with a selected pole face of the stator. The arrangement is such that in each of the ten equiangularly-spaced read-out positions of the rotor, one of the poles on the p.m. (carried by the rotor) is centrally aligned with one of the five stator poles. While this structure is perhaps interesting, it is unsatisfactory for accomplishing the objectives of the present invention.
Still another sensing means is disclosed in U.S. Pat. No. 4,101,829. In this '829 patent, a ferromagnetic body has a pair of parallel bores formed therein to receive respective conductors. These parallel bores are connected by a communicating through slot. A third bore is formed in the body, at right angles to the parallel bores, for receiving a reed capsule switch. The purpose of this patent is to provide a differential current detector. Although interesting, it is nevertheless unsatisfactory for purposes of remote meter reading.
Thus, it will be appreciated that the prior art patents and commercial devices intended as solutions to a particular problem of long standing, namely, a remote meter reading means for household purposes, have been generally unsatisfactory. Accordingly, and to the best of my knowledge and belief, these devices have not been commercially successful to any appreciable degree. Moreover, the structures and circuits in the sum total of the prior art, while perhaps bearing a superficial resemblance to certain aspects of my disclosure, are nevertheless intended for altogether different applications and hence are wholly unsuitable for the intended purposes of my disclosure.